Dust control can be a particular problem on construction sites, building demolition sites, excavation sites and mine sites. For example, in a mining operation, the mine haul roads essentially consist of dirt and gravel. Dust control is necessary on the haul roads so that the operators of mining vehicles can readily see the other mining vehicles using the roads. Thus, dust control on mine haul roads is a safety issue. Moreover, dust clouds caused by vehicles operating on the haul roads can adversely impact air quality potentially creating environmental issues particularly where the dust clouds drift beyond the mine site.
Typically, mines have water tanker trucks, which are used to water down the haul roads in order to control dust. Such water tanker trucks generally have a plurality of spray nozzles positioned on either the forward or rearward sections of the vehicles to dispense a fluid spray or mist onto the ground. The water tanker truck can also have hoses or a water monitor/cannon for washing down other mining equipment and, in some cases, fire control.
Because of the service demands on such water tanker trucks, they are typically capable of carrying very large quantities of water. For example, water tanker trucks used in mining operations can have fluid capacities of over 50,000 gallons. Of course, vehicle stability is a critical issue when transporting large volumes of water that, in the case of a 50,000 gallon tank, can carry a water load of over 200 tons. Specifically, surging and wave motion of the fluid, particularly transverse surging resulting from centrifugal forces experienced during turning of the truck can cause a tanker truck to become unstable or even turn over on its side. To prevent such surging of the fluid, the tank is provided with internal baffles.
To ensure a long-life, the interior of the tanks must undergo periodic maintenance. For example, to protect against corrosion, the interior surfaces of the tank may need to be periodically cleaned and re-coated with a rust protection coating such as an epoxy. This work is complicated by the fact that tanks only have points of entry on the top of the tank and often just a single point of entry, and thus the work is subject to confined space safety regulations. Accordingly, workers performing tasks inside the tank must be provided with secondary air sources from outside the tank. This can greatly complicate the maintenance operations. Moreover, it can be difficult for the workers to maneuver around the internal tank baffles particularly since the interior of the tank is very dark. Accordingly, maintaining the interior of these tanks can be a difficult and time-consuming process.
Another problem with these types of mobile tanks is that at larger sizes they can be difficult to ship to the location at which they are to be used, typically on off-highway trucks. For instance, the largest tanks can be over twenty feet wide. As can be appreciated, transporting a tank of this size can be a difficult and expensive operation.